| Word | Definitions | Synonyms |
|---|---|---|
| keystone | (noun) the central building block at the top of an arch or vault | Synonyms: headstone, key |
| (noun) a central cohesive source of support and stability | Synonyms: anchor, backbone, linchpin, lynchpin, mainstay | |
| keystroke | (noun) the stroke of a key; one depression of a key on a keyboard | Synonyms: key stroke |